Dear Readers, when the damselflies come back every year, it always feels as if summer has truly arrived. This year there are three of these azure damselfly males, each guarding a distinct area of the pond. They are consummate fliers, and to me they look like sparks, arcing and crackling. When one of the males settles down and is approached by another, he raises his abdomen in what looks like an insect equivalent of a ‘V- sign. No doubt they are waiting for the ladies to turn up, and in the meantime they are getting tetchy and aggravated.
When the females do arrive, they will have green metallic heads and thoraxes: there is a green form and a rather rarer blue form. The whole mating process always looks a bit confusing – the male grasps the female at the back of the head, and the female moves her abdomen around under the male’s upper abdomen to collect the sperm. Many mating couples may collect at a pond because there is safety in numbers, and predators get confused if there are many choices (as we saw previously with the fledgling starlings). The females will lay their eggs in floating vegetation, of which the pond currently has a fine collection. The ferocious little larva will live for up to two years before climbing up on some vegetation, and gradually wriggling out of its carapace.S/he will then fly off to try to find a mate in the meagre five days of life that he or she has left.
There are many species of blue damselfly in the UK, and the whole thing can be very confusing. Azures, however, are extremely blue, and on the side of their thorax there is a broken line, which you can just about see in the photo below.
Although damselflies don’t have quite the wow-factor of the bigger dragonflies (like the emperor who was trying to lay eggs on my wooden steps a few years ago) they are the most delicate and fairy-like of insects. They are not as agile in the air as a dragonfly is, so they behave more like flycatchers, waiting on a ‘perch’ to fly up and grab a passing insect. If I was one of the tachinid flies that are also haunting the pond I would be a little bit careful.
These flies are a regular feature around the pond in early summer, and they seem to be another territorial species, seeing off any other flies that approach. The little battles of the garden are so often overlooked, but in truth everyone seems to be sparring for room to live, for mates and above all for the chance to reproduce. These flies are important pollinators of daisies and members of the carrot family, but their larvae are parasites. The female lays her eggs on the foodplant of the larvae of certain moths, such as the gypsy moth (a notorious muncher of pine forests) and the pine beauty (which is rather less voracious). The caterpillar eats the eggs with the leaves, and the single larva that develops eats the poor moth from the inside. The fly has been suggested as a method of bio-control for the gypsy moth, though such plans have a history of having unintended consequences.
This is a very handsome fly though, no?
I often wonder what it would be like to experience the world through the compound eyes of a fly or a damselfly, and my imagination fails. How does the insect put all those images together to form a meaningful picture? What does each tiny lens actually ‘see’? Apparently compound eyes are normally excellent at detecting movement but have low resolution. However, the eyes of the dragonfly family have special zones with slightly different lenses, which do allow the insect to hone in on its prey with great precision. A dragonfly has over 24,000 separate ‘lenses’ in each eye – the eyes almost meet in the middle of the head, as if the animal is wearing a helmet. Just as it is impossible (for me at least) to imagine a colour that doesn’t currently exist, so the world of these creatures feels as difficult to comprehend as that of another planet. And yet, I have been circled by an emperor dragonfly, and have rarely felt so closely inspected by another creature. We might not be able to think ourselves into their world, but there is no doubt in my mind that they have seen us.